CleanStart: stress-free cold glue application

Cold glue application and production stoppages are not a good match. It takes just one to two minutes for cold glue to dry on the nozzle tip of the application head. Nozzles therefore need to be covered in a way that is airtight. For short interruptions, this is handled by the automatic nozzle closure. We tested the performance of our CleanStart nozzle closure on a folder gluer at Flatz GmbH. Read all about the interesting insights Flatz gained from the test in this blog post.

The CleanStart nozzle closure on Robatech's Sempre application head guarantees stress-free cold glue application.

Stops at the folder gluer are part of everyday production. 

These include: 

  • Setup operations to adjust and test folding and guiding aids when changing formats 
  • Work-related and shift-related breaks
  • Unplanned functional disruptions
  • Upstream or downstream material interruptions. This could be, for example, a lack of material supply at the feeder or a failure in the binding machine with boxes stacking up on the pick-up table.  

Cleaning cold glue nozzles costs valuable time

When production stops, the flow of cold glue in the application valve also stops. After just one to two minutes, the cold glue forms a delicate skin after coming into contact with the air. This skin stretches over the nozzle opening and causes the dispersion adhesive to be deflected or to come out in excessively small quantities when restarted. If things are stopped for longer, the nozzle can even become clogged. 

Without a closing device on the nozzle, operators have to clean the nozzle tips with a wet cloth before starting up. This is the only way to prevent rejects or unplanned downtimes. In the case of a folder gluer 15 to 30 meters long with several cold glue units and 6 to 24 application heads, cleaning can turn into a marathon effort, involving precious time that could be better used for essential tasks at the feeder or pick-up table.  

The nozzle closure solution 

A nozzle closure prevents cold glue from drying out at the nozzle opening. During production downtime, a narrow sheet with a rubberized surface automatically slides under the outlet opening of the application head. 

The arc-shaped movement in which the sealing plate slides under the nozzle opening guarantees the reliability and longevity of the CleanStart nozzle closure.  During a production stop, the CleanStart nozzle closure covers the nozzle opening so that it is airtight. 

In practice, this sealing plate should be durable and move into the exact position during each closing operation. Only in this way can a 100% airtight sealing of the opening be permanently guaranteed. If the closing mechanism causes any abrasion, the cold glue could come back into contact with air and dry out. This would mean more cleaning efforts again. When purchasing a cold glue unit, you should therefore pay attention to how reliably a manufacturer’s nozzle closure works.

How well does CleanStart work?

Does Robatech’s CleanStart nozzle closure seal a nozzle airtight and provide clean start-up behavior? We wanted to prove it and tested CleanStart at Flatz GmbH in Lauterach, Austria. Flatz develops and produces custom-made, sustainable packaging solutions made of cardboard, corrugated cardboard, molded pulp, and particle foams, as well as technical components, for a wide variety of industries. 

Flatz GmbH building in LauterachTest run of the CleanStart nozzle closure at Flatz GmbH in Lauterach, Austria.

For the test run, Flatz installed two Robatech Sempre heads. After approximately three months of applying adhesive to corrugated cardboard boxes, the employees of Flatz took stock of the CleanStart nozzle closure.    

No rejects when starting up

"Thanks to CleanStart, the cold glue head immediately delivered a perfect glue bead after a stop, enabling production to run more smoothly. All properly placed boxes were able to be used, even during the setup process. Once the machine was released, we were able to continue production immediately without any glue-related rejects."

Time savings

"No one had to run to the opposite side of folder gluer to clean the nozzles at the gluing unit. Especially with larger items, this was a pleasant and extraordinary result. It enabled us to greatly reduce downtime. Employees were able to be where they were really needed, for example at the display."

"Especially in terms of minor malfunctions without any retrofitting required, we were able to speed things up by 30–50% thanks to CleanStart. The time savings were particularly noticeable during short runs, as no time was wasted on cleaning the nozzles during the frequent setup operations."

Sempre cold glue head with CleanStart nozzle closureThe time savings with CleanStart are particularly noticeable during short runs.

Pleasant working

"All in all, CleanStart reduced stress at work for machine operators. The collector was able to switch off the feeder and turn it back on at any time without worrying about the first cartons being produced without any glue. Employees were spared useless walks for cleaning the cold glue heads."

Long service life

"We were amazed at how the arc-shaped movement, in which the sealing plate automatically moves under the application nozzle, proved to be very beneficial. We did not notice any significant wear and tear during the test."

Stress-free, reject-free cold glue application

The test proved that stress-free working with cold glue application heads is possible. A reliably functioning nozzle closure

  • relieves your employees,
  • reduces reject production after machine stops,
  • and reduces downtime. 
When purchasing a cold glue unit, you should therefore include the nozzle closure– usually offered as an optional component – into your evaluation criteria. 

Are you already using cold glue application heads with nozzle closures? Let us know about your experiences in the comments.




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